1. Field of the Invention
The present invention relates to a photoreceptor such as a photoreceptor drum, a cooling mechanism for the photoreceptor, and an image forming apparatus provided with the cooling mechanism for the photoreceptor.
2. Related Art
In an image forming apparatus such as a copy machine and a printer, a photoreceptor such as a photoreceptor drum of which the surface is uniformly charged by a charging device is exposed and scanned by an optical scanning device, and an electrostatic latent image corresponding to image information is formed on the surface of the photoreceptor. Thereafter, the electrostatic latent image formed on the surface of the photoreceptor is developed by a developing device using a toner as a developer, and is visualized as a toner image. The toner image is transferred onto paper by a transfer device, and then heated, pressurized and fused onto the paper by a fusing device. The paper onto which the toner image is fused is ejected to the outside of the apparatus. The sequence of image forming operations is thus completed.
In an image forming apparatus, for example, a flange is attached to each of both ends in an axial direction of a cylindrical photoreceptor drum. In addition, the photoreceptor drum is rotatably supported by a main body frame via a rotational shaft inserted into the axial center thereof and shaft bearings that support the rotational shaft. The photoreceptor drum is rotationally driven at a predetermined speed by a driving force from a drive source.
In a case where the photoreceptor drum that supports a toner image on a surface thereof is heated as described above and the temperature of the photoreceptor drum rises above the melting point of the toner, problems arise such as the toner fusing onto the surface of the photoreceptor drum. To address the problem, cooling of the photoreceptor is performed by introducing air flow inside of the photoreceptor drum.
However, in an image forming apparatus configured such that a rotational shaft that is inserted into the axial center of the photoreceptor drum is rotatably supported by a main body frame via shaft bearings supported by a holder, the holders supporting the shaft bearings block a through hole of one of flanges of the photoreceptor and prevents efficient discharge of air flow circulating inside the photoreceptor to the outside thereof. As a result, there has been a problem in that the cooling performance of the photoreceptor declines.